Utility of Different Lung Ultrasound Simulation Modalities Used by Paramedics during Varied Ambulance Driving Conditions.

Introduction: Prehospital use of lung ultrasound (LUS) by paramedics to guide the diagnoses and treatment of patients has expanded over the past several years. However, almost all of this education has occurred in a classroom or hospital setting. No published prehospital use of LUS simulation software within an ambulance currently exists.

Study Objective: The objective of this study was to determine if various ambulance driving conditions (stationary, constant acceleration, serpentine, and start-stop) would impact paramedics' abilities to perform LUS on a standardized patient (SP) using breath-holding to simulate lung pathology, or to perform LUS using ultrasound (US) simulation software. Primary endpoints included the participating paramedics': (1) time to acquiring a satisfactory simulated LUS image; and (2) accuracy of image recognition and interpretation. Secondary endpoints for the breath-holding portion included: (1) the agreement between image interpretation by paramedic versus blinded expert reviewers; and (2) the quality of captured LUS image as determined by two blinded expert reviewers. Finally, a paramedic LUS training session was evaluated by comparing pre-test to post-test scores on a 25-item assessment requiring the recognition of a clinical interpretation of prerecorded LUS images.

Methods: Seventeen paramedics received a 45-minute LUS lecture. They then performed 25 LUS exams on both SPs and using simulation software, in each case looking for lung sliding, A and B lines, and seashore or barcode signs. Pre- and post-training, they completed a 25-question test consisting of still images and videos requiring pathology recognition and formulation of a clinical diagnosis. Sixteen paramedics performed the same exams in an ambulance during different driving conditions (stationary, constant acceleration, serpentines, and abrupt start-stops). Lung pathology was block randomized based on driving condition.

Results: Paramedics demonstrated improved post-test scores compared to pre-test scores (P <.001). No significant difference existed across driving conditions for: time needed to obtain a simulated image; clinical interpretation of simulated LUS images; quality of saved images; or agreement of image interpretation between paramedics and blinded emergency physicians (EPs). Image acquisition time while parked was significantly greater than while the ambulance was driving in serpentines (Z = -2.898; P = .008). Technical challenges for both simulation techniques were noted.

Conclusion: Paramedics can correctly acquire and interpret simulated LUS images during different ambulance driving conditions. However, simulation techniques better adapted to this unique work environment are needed.